A Quick Introduction to IP Addresses

IP (Internet Protocol) addresses are ways of identifying unique internet-accessible devices. They are also ‘addresses’ in the sense of showing its location (think of postal addresses).

Background

When you type a web page into the computer, what you’re really asking is for some information from a different device (usually a big server somewhere in the world). There are several complex stages to finding this, but one of the key components is having an identifying ‘marker’ on each device; so you know which address to get the information from, and also so the information knows how to get back to you.

IPv4

Recently, we’ve been running out of traditional (IPv4) IP addresses: using 4 different 32 bit numbers (eg. 93.184.216.119), giving us access to 4,294,967,296 possible unique addresses (2³²)).

IPv6

IPv6 uses 2¹²⁸ numbers, which is quite a bit bigger (340,282,366,920,938,463,463,374,607,431,768,211,456). An example of one of these is: 2001:db8:0:1234:0:567:8:1. To put that in perspective, 2¹²⁸ E. coli bacteria (which are pretty small) would be around 26 times heavier than Earth (which is pretty big).

Take home point is we’re not going to be running out of IP Addresses soon.